Heat exchanger



Jan. 27, 1931.

H. .w. Howl HEAT EXCHANGER n 2 Sheets-Sheek 1 Filed Feb. 29

Jan. 27, 1931. H. W. How `1,790,151

HEAT EXCHANGER n Filed Feb. 29, 192e 2 sheets-sheet 2 Z5 Z6 l 35 37 dan. 27,

UNITED STATES PATENT Orr-ICE nAnLAN w. now, or WARREN, rENNsYLvANIA, AssIGNon 'ro srnu'rnmswnus conm, or WARREN, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA BEAT nxcnaNGnn Application led February 28, 1928i. Serial Nc. 257,830.

This invention relates to heat transfer apparatus of a tubular character whereby heat istransmitted from .a vapor or steam to a' 'cooler liquid, or the heat is transmitted from a hot liquidv to a cooler liquid, one liquid `flowin on the one side of the tubes and the other i uid or vapor iiowing on the other side of t e tubes.

The ordinary type of apparatus isdesigned with the requisite square reet of transmitting surface arranged in a single shell and the tubes and the heads being laid out so that the liquid flowing in the tubes makes several passes before finally emerging from the heater.

The reason for the multiple passes is to secure a totaltravel oftube length sucient to heat or cool the liquid to the desired point.

Oneof' the principal factors in the design 2o vof such a paratus is to keep the velocities of x the liqui commercially .practical without-too great an expense for-pumping. The higher the velocity the eater thev transfer of heat per unit of surfrce through the tubes.

For instance, when we obtain a heat trans- A fer of say220 degrees at a` velocity of 2 per A second, we would obtain a heat transfer of approximately 500 degrces,if the speed is so increased to 10' per second. A goed practical velocity is between and 8 per second.

On the above basis a heat transfer of approximately 400 degrees to 460 degrees would beobtained. This condition holds true not only -with the speed of liquid but also with the speed of the steam or vapor over the tubes.

Such apparatus is used for several purposes; one is the transfer of heat from a hot liquid to a colder liquid in ordervto recover the heat from the hot liquid; another is the heating up of the liquid by means of vapor or steam for the urpose vof heating the hquid; another is the eating of the liquid byI means of vapor or steam in order to condense the vapor or steam. 1 p

The present heater is designed to p rvide a Yrapid circulation or a'high'velocity of the li"'uor'*both within the tubes and on the out- Aside of the tubes. In the ordinary type of apparatus ilpro- Various means have been. ued to increase as high as possible or as highk as klar-jacket or wall of hexagon shape is placed locity and length ofv passages, also to provision vis successfully fmade to insure a high velocity Where the liquid is carried within the tubes, but where the liquid is circulated on the Ioutside of the tubes the velocity is extremely low due to the wide spacing of the es tubes, the large waste space in the large shells required, and the space between the tube banks in 'the heads to provide the returnpaths for the liquid. Y e

the velocity of the outside of the tubes or to direct the liquid across the jtubes rather than axially 0rlengthwise thereof by means of baiilesvof sheet metal.

In some cases the inside of the shell has been filled withl a sheet metal spiral runnin `fromone end to the other, with the iiig ts closely pitched. The object of this spiral is to direct t Ie liquid in a path at i.

approximate rightangles to the tubes, and rovide a. long glow path. None of these evices has succeeded lin increasing the velocity ofv flow to the extent necessary for elicient heat transmission.

The present heater is sc designed that the speed of the liquidin unit quantities is approxmately the same on the outside of the l tubes as lit is on the inside of the tubes.

This is effected by spacing the tubes very closely together and using very thick tube sheets in order to have the sheets strong enough to Awithstand the rollin action of the," tube expander when the tu es are inserted and made tight, and the tube bundle isarranged inthe orm of a. hexa on. Even this arrangement if used as descri d would s till leave too much waste space to maintain the velocity at the proper point. 4In order'to cut down this waste space, a tubuaround the tube bundle. .y

The object of .this invention is to obtain a greater heat transference for-a given vevide for afunit construction which reduces the cost of manufacture andalso'permits of readily increasing the capacity of .the apparatus where desired; and which permits vapors -and liquids to flow with a streamline which encounters the minimum resist- Flg. 4 is a vertical section, on an enlargedl scale, taken on line 4 4, Fig. 1.

Fig. 5 is a fragmentary view showing the saddle for supporting the adjacent 'parts of two shells relatively to one another.

Fig. 6 is a fragmentary,longitudinal section on an enlarged scale, of the left end-portion of one of the units ofthe heatI exchanger. c

Fig. 7 is a similar view of the central part of this unit. Y

Fig. 8 is a similar view of the right end portion of this unit.

Fig. 9 is a view similar to-Fig. 7 but showing a modified form of the baliie vfor supporting the tubes in the central part of the shell.

Figs. 10 and 11 are fragmentary longitudinal sections,`showing modified forms of the joints between the tube sheets and the shell of the heat exchanger.

Fig. 12 is a vertical section taken on line 12-12, Fig. 5.

Fig. 13 is a fragmentary vertical section taken on line 13-13, Fig. 11.

Similar characters of reference indicate like parts in the several figures of the draw- 1n z .lhe improvements in this `heat exchanger are embodied in a single unit of the same which is so designed that a plurality of such units may be assembled for producing a lheat exchanger of any desired capacity. In the preferred construction each of these units is provided withan outer tubular shell or enclosing casing consisting of a central section 20, two intermediate sections 21, 22 and two outer end sections 23, 24. The central section has preferably the formof a straight horizontal tube which is provided at its opposite ends with external coupling flanges 25. Each of the intermediate sections is provided With a. straight body the inner end' of which is provided with an external flange 26 which is connected byV bolts 27 with the flanges 25 on the adjacent end of the central shell section, andbetween its ends each intermediate shell section is provided with an inner nozzle or branch, which nozzle on one intermediate section extends upwardl as shown at 28, and on the other intermediate section this nozzle ,extends downwardly as shown --at 18 'in the preferred manner of assembling the units. Each of the end'sections of thehell is of elbow form engages with the outer end of a rabbet 30 on the outer end of the intermediate section 21, the 'opposing ends of these sections being provided' with external ianges, 31, 32

' which are connected by bolts 33. The outer end of the left section 23 forms an outer nozzle 34 which in the present case is turned upwardly. The other end section 24 has its inner end provided with a gland 35 which engages with a rabbet 36 on the outer end of the right intermediate section 22, the opposing ends of these sections being provided with external flanges 37, 38 which are connected by bolts 39. The outer end of the right section 24 forms an outer nozzle 40 which in this case projects downwardly.

In assembling the shells of a plurality of such units these units are preferably placed one above the other to form a vertical tier but alternate units are reversed so that the downwardly turned inner and outer nozzles at one end of one unit will register with the upwardly turned inner and outer nozzles of the other unit and the corresponding nozzles of the two adjacent units communicate with each other. The shells of adjacent units are connected by bolts 41 passing through the dan es 42 on the corres onding outer'` nozzles and olts 43 passing tlirough flanges 44 on the corresponding inner nozzles of the shells, as shown in Fig. 1.

On the outer side of each end shell section the same is provided with a hole or opening 45 for inspection, cleaning or repairing, which is normally closed by a cover or plate 46 removably secured thereto by screws 47 or other suitable means. Arranged lengthwise in the central and intermediate sections of the shell is a bundle or group of tubes, pipes or iues 17 which are spaced apart from each other and also from the walls of the shell 'sections containing them and which communicate at their opposite ends with the chambers formed within the elbow shaped end sections of the shell. The most compact arrangement of the bundle Vof tubes which still leaves a clearance between them is best obtained by arranging each tube opposite thespace between two opposing tubes'so th'at as a whole the tubes are stag-l gered relatively to each other and the bundle as a whole is substantiall hexagonal in cross section while the bore 0 the shell section is cylindrical in cross section. These tubes are made of comparatively heavy stock andthe opposite ends of the same pass through openings in transverse tube sheets 48, 49 which latter are made of comparatively thick stock so 'slidable" or floating lengthwise thereon to -thereby permit the tubes and shell to .expand and' contract independently of each other in response to variations in temperature withf out liability of straining, breaking or injuring any parts. In the preferred construction this is accomplished b extending the marginal part of t e tube s eet 48 into the rabbet 30 and clamping the same between the bottom of this rabbet and the gland 29v so as to hold this tube sheet against movement. If desired packing rings or gaskets 50 maybe arranged between .the tube sheet and the rabbet30 and gland 29 so as to form a Huid tight joint between the same. The other tube sheet 49-is free to slide lengthwise by engaging its .periphery with a packing'arranged in the other rabbet 36 of the shell' which packing may consist of a plurality of packing rings 52 and ai follower ring 53 arn ranged in the rabbet 36 between the bottom thereof and thegland 35, thereb forming a stuting box'which rovides a lea tight joint between the tube s eet 49 and the shell and still permitting this sheet to slide in the shell.

It desired the joints between the tube sheets and the shell may be so constructed that any leakage which may occur in these joints will be conducted to the exterior of the apparatus where it Awill be visible to attendf ants and thus lead to prompt adjustment of the ,packings in these joints which will prevent further leakage. Means suitable for this purpose are shown in Figures land ll.'4 ln Fig; l0 the periphery. of the fixed tube sheet 48 is provided with an annular leakage groove 54 and the adjacent part of the rabbet is provided with a vent opening 55 leading to the atmosphere. 'If any leakage should occur in the joint between-the tube sheet 48 which would permit fluid to pass from the elbow section to the groove 54 such leakage would find its way through the vent opening 55 to the exterior when the same would be detected, and similarly any leakage of fluid from the space around the tubes to the' groove 54 would be likewise conducted by the opening 55 to the exterior and consequently observed. As shown in Figs. 11 and 13, anyv leakage past the packing between the sliding tube sheet 49 from either side of the tube sheet escapes to the exterior of the shell through the vent opening 62, the acking beshell. Any

tween .these -follower rings lis arranged an .openwork ring 59 having preferably the form exterior, therebypreventing mixing of the fluids -on the inner and outer sides of the tubes which is very'important,particularly when contamination of one of these fluids by the other must be avoided. -v i In using this apparatus for exchanging heat vbetween one fluid and. another, one of these fluids is passed through the inside of the tubes in one direction `and the other fluid is passed through the shell on the outer side ofthe tubes in the opposite direction, whereby the .temperature of one fluid is raised 4rand the other lowered, assuming that the fluids were of unlike temperatures before passing through this apparatus.

When using this apparatus for raising the temperature of cold oil by means of hot oil which has just been heated during the process of treating of the same it will be assumed that the cold oil enters through the outer, upper nozzle 34 at the left side of the upper unit and that the hot oil is admitted through the lower inner nozzle 44 at the left end of the lower unit4 shown in Fig. l. In such a case the cold oil would first passfrom the left to the right end of the tubes in theupper unit, thence throughthe elbows of both units at theright ends thereof, thence through the tubes in the lower unitfroni the .iight to thc left ends thereof, and thence out throughthc .outer nozzle 40 of the left elbow of the lower of the lower unit, thence through the lower 'f sh-ell around thetubes in the lower unit, from the left to the right end thereof, thence through the inner nozzles at the right ends of the units, thence througl'i the shell of theA upper unit and around the tubes therein from out through the' inner upper nozzle 28 at the left end of the upper unit.

' The fluid by these means is caused to flow in steady stream lines through the shell and tubes, without meeting with any obstruction which would cause a sudden deflection or the right to the left end thereof, and thencey change of course in thevdirection of flow of the fluid, this being due to the fact that the elbows and nozzlesat the ends of the units, ,cause the fluid to 1lie-gradually reversed in its flow, thereb avoiding undue checking of the flow of fiui and maintaining the capacity ofthe heat exchanger accordingly.

One of the distinguishing features of thisy heat exchanger is its small diameter and extraordinary length.

ln order to i )reventthe tubes from sag` ging midway ofi their length and possibly engagingwith each other when they are of considerable length and thereby reducing the eiliciency ot' the appalatus means are provided which will support the tubes between their ends without however interfering with the flow of the fiuid through the shell. As shown in Figs. 2, 2i, and 7 these means consist of a helical web 63 ofv metal which bears with its outer edge against thel central part of the. bore of the central shell section and provided with a plurality of openings n(Sal through which the tubes pass andare thereby support# ed onthe shell and also maintained in the proper space position relatively to each other so as to secure the maximum heat exchange efi'ect without obstructing the passage of the fluid through the shell. Substantially the same eii'ect is obtained by means of two brack ets 65, 66 secured tothe top and bottoni of the central shell section but spaced apart and provid-ed with openings for the receptie'ngofl the tubes the said brackets being supported on the shell and maintained .in spaced relation. y

If the flow of the fluid through the shell is constantly in the same direction, 'these brackets may be inclined in the same direction in which the stream of fluid flows, as shown in Fig. 9, inasmuch as such inclination avoids any appreciable interference with the flow et' the stream ot fluid. When howeverthe flow of the stream may occur in either direction through the shell these brackets are arranged at right angles to the axis of the shell so as to have the same battling cfl'ect on the stream both ways. i I i A cylindricalform in cross section of the centralv and intermediate sections of the 'shell is the most desirable andveconomical on account ofthe greater ease and facility with which the same can be made. This form of the central and intermediate sections ofthe shell, however, leaves too much space between the bore of these shell sections and the periphery of the bundle of tubes to permit of maintaining a sufficiently highl velocity of the fluid to secure the desired capacity. Means are therefore, provided for reducing the effective space within the shell around the tubes and bringing it into substantial conformity to the cross sectional form of the bundle of tubes. These means preferably ccmprise a tubular inner wall or jacket consis-ting of two sections 67, 68l each of which is of hexagonal' form in cross section and surrounds the bundle oftubesbetween the central tube support and one end of the central. Y. shell section s o as to form -an annular dead,rspace 69 between ythe periphery of each inner wall Asection and the adjacent part of lthe bore of the vcentral shellsection. AAt (its.

ring is provided with a plurality of openings 72 so that fluid may enter the dead space 69 and thereby balance the pressure on the opposite `.sides of the contracting wall section.

By making-the rings 90 solid or unprovided with openings Vinvits rim the fluid cannot flow through the dead spaces 69 but any Huid enteringthe same remains dormant therein.

The inner ends ofthe two sections of the inner wall sections preferably engage against oppositesides of the helical tube supporting web, as shown in'v Fig. 7, thereby holding this support against lengthwise movement 1n the s'hellunder the'pressure ofthe stream of fluid without, requiring the support to be fastened to the shell. l

Means lare provided whereby these ends of adjacent shells' which are not in communication with each other are supported one upon another and maintained inspaced relation and still are free to slide lengthwise one relative to another. This is preferably accomplished by a saddle 7 3 interposed between the disconnected ends of two adjacent shell units which is providedat its upper end with a jaw 74 embracing the adjacent opposing fiangeson the shell sections of the upper unit l and a shoe 75 at its lower ends which is capable of sliding on the adjacent opposing flanges on theshell sections of the-lower unit, as shown in Figs. 1, 5, and 12. It follows from this form of saddle that the disconnected ends of the shells of superposed units are free to move lengthwise.k independently of each other due to variations in temperature without rupturing any of the parts.

By cutting down the waste space in this heat exchanger, a very high velocity of the fluid through the space outside of the tubes is obtained and a corresponding increase in capacity. This velocity is not appreciably affected by the helical support for the tubes lecause it offers but little resistance to the The fact that the elbow shaped outer sections and the T-shaped intermediate sections vat opposite 'ends of each unit are identical 1n construction reduces the cost of manufac- '5 /ture, permits re lacement without dilculty;

reduces the num 'r ofspare parts which have.

to be carried in stock, and also permits extension or enlargements of the heat exchanger to be made later on easily, readily and withc out disturbin or discarding any of the parts already instal ed.

lation.

Instead of'operating this heat exchanger on the counter current .principle previously described the same may also be operated by vus running the two fluid paths within and without the tubes in parallel.

It is also ssiblelto run the apparatus so that one o the fluid paths of the several units ma low in parallel and the other fluid paths o the several units may be run in series. Other combinations are possible to suit the requirements of a particular instal-'- shells of adjacent units could also be separated and the lower T turned to the side to take the vapor while the condensate leaves each unit independently.

Owing to the manner ot mounting the `tube sheets in the shell those sheets cannot tiltand therefore, the tubes are always maintained in their proper position.

Iclaim as my invention Y l. A heat exchanger comprising an outer shell provided at each end with an outer nozzle and an inner'nozzle, one ot which forms an inlet and the other an outlet, tube sheets arranged within the shell andeach extending across the space thereinbetween the outer and inner nozzle at one end thereof, tubes ar:-

ranged in the shell and mounted atx-opposite ends on said tube sheets so as to communicate with said outer nozzles, a wall in the space within the shell between the inner nozzles thereof and around the adjacent parts of the tubes, and forming a dead'space between said Walls and the shell, and means for supporting said wall on said shell having passages which establish communication between the spaces on opposite sides of said wall, comprising a ring surrounding each end. of said Wall and engagin the inside of said shell, one of said rings eing provided 'with open- 1n s A heat exchanger comprising an outer shell having an inner and an outer nozzle at each end, a tube sheet within the shell at each end between the respective inner and outer nozzles, tubes arranged lengthwise in theshell' and' supported at opposite ends on the-tube sheets and communicating with said outer nozzles, a support for said tubes between the ends thereof, andan inner wall eonsistingof sections Aarranged within the shell around the tubes and abutting against said support;

3.."A heat exchanger` comprisingan router shell having an inner. and an .outer nozzle at c each-end, a tube sheet within the shell at each end between the respective inner .and outer nozzles', tubes arranged .lengthwise in the shell and supported at opposite ends on the tube sheets and communicating with said outer nozzle a support for said tubesv between the en s thereof, an inner wall consisting of sections, arranged within the shell around the tubes rand abutting against said support, said support having parts arranged at an angle to the axis of the shell.

4. A. heat exchanger comprising an outer shell having'an inner and anouter nozzle at veach end, a tube sheet within the shell at each end between the respective inner and outer nozzles, tubes arranged lengthwise in the shell and supported at opposite ends on the tube sheets and communicating with said 7outer nozzles,a support for said tubes between the ends thereof, and an inner wall consisting of sections arranged within the shell around the tubes and abutting against said support, said support having the form of a helical web and provided withl openings i through which said tubes pass'.- 5. A heat exchanger comprising an outer shellhaving an inner and an outer nozzle at each end, a tube sheet within the shell at each end between ,the respective inner and outer nozzles, tubes arranged lengthwise in the shell and supported at opposite ends on the tube sheets and communicating with said outer nozzles, a support for said tubes between the ends thereof, an inner wall consisting of sec-i tions arranged within the shell around the tubes and abutting against said support, and rings supporting said wall sections on the inner side of said shell. A

6.- A 'heat exchanger comprising a shell having a tubular central section, two intermediate sections arranged at opposite ends of the central section and each having an inner nozzle, and two outer sections arranged at the outer ends of said intermediate sections and each having an outer nozzle, tube sheets arranged in the shell adjacent to the joints between said outer and intermediate shell sections, tubes arranged within the shell and mounted on said sheets, a tubular inner wall arranged within'the shell and around said tubes, and supporting rings which carry said inner walls and which are secured in the joints between the outer ends of said central shell section and the inner ends @t said `intermediate shell sections,

iso

. ity of shells each of which is provided at its opposite ends with outer nozzles which projectvfromopposite sides of the shell and with inner nozzles which project in opposite directions from the shell, the outer d inner nozzles at theY corresponding ends' of two shells communicating with each other, tube sheets arranged in each shell between the inner and outer nozzles thereof, tubes arranged in each shell and mounted at opposite ends on'the sheets therein, said 'shells being provided, adjacent to their ends, with peripheral flanges, and a saddle which is interposed between the opposite disconnected ends of adjacent shells and which interlocks at one edge with'the flanges of one shell and slides on the flanges of the other shell.

8. A heat exchanger comprising a plurality of shells each composed of a central section, intermediate sections secured .to the ends of said central section and having laterally extending nozzles and elbows secured to the ends oi said intermediate sections, the elbow and nozzle at one end of each shell projecting 4in the opposite direction from the nozzle and elbow at the opposite end of said shell and all substantially an equal distance from the center of the shell, means for connecting the nozzles at the corresponding` ends of the shells, means for connecting the adjacent elbows of the shells,`tube sheets arranged in the shells betweenY said nozzles and elbows, at

-least one of said tube sheets being held in v place in the joint between the elbow and the intermediate section at the corresponding end of the shell, and tubes arranged in said shells and mounted at their ends in said tube sheets.

directions from said shell, the outer and inner-nozzles at the corresponding ends of two shells communicating with each other, tube sheets arranged in each shell betweenfthe inner and outer nozzles thereof, tubes arranged in each shell and mounted at opposite ends in the sheets therein, a saddle which is interposed between the opposite disconnected ends of adjacentshells and means for removably connecting said saddle with each shell.

10. A hea-t exchanger comprising a shell having an inner and an outer nozzle at each end, a tube sheet arranged at each end of the shell and fitted with its periphery adjaj cent t-he bore of said shell, tubes arranged in said shell and mounted on the tube sheets and communicating with the outer nozzles,

' said shell being provided with at least one vent passage leading fromthe joint between at least one tube sheet and shellto the atmosphere and a packing .at said joint comprising a central annular open work ring and annular packings on opposite sides of said ring and embracing the tube sheet.

A 11. A heat exchanger comprising a shell having an inner and anouter nozzle at each ,m

end, a tubesheet arranged at each end of the shell and fitted with its periphery adjacent the bore of said shell, one of said tube sheets being fixed and the other slidable longitudinally in said bore, said shell being provided with an internal rabbet around said slidable tubev sheet, tubes arranged in said shell and mounted on said tube sheets and communlcating ivlth the outer nozzles, sald shell being provided with a vent passage lead-i elements forming said packing embracing said slidable tube sheet and age thereby.

In testimony whereof I aiiix preventing leakm signature.

'loo

los 

